Diabetes during pregnancy affects the pregnant woman and her offspring as toxemia and cesarean section are both more common in women with diabetes during pregnancy, and malformations, macrosomia, prematurity and perinatal mortality are more common in infants of diabetic mothers. Also, offspring of diabetic women are at an increased risk of developing obesity and glucose intolerance during childhood and young adulthood. The purposes of the project are to identify diabetes and impaired glucose tolerance during pregnancy in women in the Gila River Indian Community, to determine the effects of abnormal glucose tolerance on outcome of the pregnancy, and to determine long term prognosis for the women and their offspring. The diabetes status of every woman is determined at two-yearly intervals and during the third trimester of each pregnancy. The characteristics of women who have diabetes or impaired glucose tolerance during the pregnancy are compared to those of women who are normal during the pregnancy and subsequently develop diabetes and to those of women who remain normal. At birth, cord blood is collected for determination of glycosylated fetal hemoglobin, C-peptide and proinsulin, and maternal blood is also collected for glycosylated hemoglobin. These women and their offspring are followed at two-yearly intervals. It has been previously reported that offspring of diabetic women have more diabetes and more obesity than offspring of nondiabetic and prediabetic women. Birth weight was predictive of relative weight in the 5-9 and 10-14 year old offspring of nondiabetic women but not in the older age group. In contrast, for offspring of prediabetic and diabetic women, birth weight was not predictive of subsequent obesity at any age studied. Offspring of diabetic women were heavier than offspring of nondiabetic and prediabetic women regardless of birth weight. Thus, maternal diabetes was important in predicting body size in the offspring even after accounting for the effects of the birth weight and maternal body size.